Evaporator for refrigerating apparatus



NOV- l, 1932. H. c. KELLOGG ET AL l 1,885,838

EVAPORATOR FOR -REFR:l:(rER'lIIG APPARATUS Filed' April 5. 1929 `2 sheets-sheet 1 &

Trae/vnf.

Nov, 1, 1982. Q KELLOGG ET AL 1,885,888

EVAPORATOR FOR REFRIGERATING APPARATUS Filed April 5. 1929 2l Sheets-Sheet 2 #VVF/Waas: #98M C- 2% faQ/W( W.

Arrae/Vfzn Patented Nov. 1, 1932 UNITED STATES PATENT OFFICE HERBERT C. KELLOGG AND EDWARD M. MAY, OF DETROIT, MICHIGAN, ASSIGNORS TO GLEN IP. COWAN, 0F DETROIT, MICHIGAN; GRACE A. COWAN, EXECUTRIX 0F SAID GLEN 1?.,COWAN, DECEASED EVAPQRATOR FOR REFRIGERATING APPARATUS I Application led April 5, 1929. Serial No. 352,673.

The invention relates to evaporators for mechanical refrigerating systems and has to do especially with evaporators of the flooded type. In most of its aspects, furthermore, the invention has to do with evaporators operating on the principle disclosed in our pending applications Serial No. 295,174, filed July 25, 1928, and Serial No. 351,372, filed March 30, 1929.

One of the objects of the present inventlon is the provision of an evaporator of the fiooded type having a float valve for controlling admission of liquid lubricant whlchl 1s characterized by a fioat of open construction and which is therefore not subject' to collapse from high gas pressure and which 1s exceedingly simple and susceptible of production at low cost.

Another object of the invention is the provision of an evaporator of the character set forth in said application Serial No. 295,174 which is adapted to receive all working connections with the liquid and gaseous refr1gerant lines through an upright wall of the evaporator, thus adapting the latter for those applications in which the refrigerant lines cannot conveniently be carried ofi.' from the top wall of the evaporator.

A further object of the invention 1s the provision of an evaporator of the character last referred to which is capable of being produced at low cost.

Another ob ect ,of the invention is theprovision of an evaporator of the flooded type which is adapted to prevent objectionable frosting and defrosting actions on the eX- terior of the evaporator incident to differences of temperature between different parts of the evaporator casing.

Other objects of the invention more or less incidental or ancillary to those above noted will be apparent from the following description in which the invention is set forth in conjunction with the accompanying drawings illustrating some of the preferred ernbodiments of the invention.

In the drawings, Fig. 1 is a vertical longitudinal section through an evaporator embodying the invention.

Fig. 2 is an end elevation of the same evaporator.

Fig. 3 is a section on the line 3--3, Fig. 1.

Fig. 4 is a fragmentary sectional view illustrating a modified form of construction of oFne of the features of the evaporator shown in Fig. 5 is a fragmentary view similar to Fig. 4 but showing one of the parts of the structure in process of formation.

Fig. 6 is a Vertical longitudinal sectional view of a modified form of evaporator.

Fig. 7 is a section on the line 7-7, Fig. 6.

Referring in detail to the form of construction shown in Figs. 1, 2 and 3, the casing of the evaporator comprises a drawn steel shell 1 which constitutes the cylindrical side wall and onev end Wall of the casing, and a separate relatively heavy metal plate 2 which constitutes the other end wall of the casing. The shell 1 is formed adjacent the plate 2 with an inwardly projecting bead 1a which forms an abutment for the inner side of the plate 2 and the adjacent end of the shell 1 is flanged inwardly atlb so that the end wall 2 is tightly clamped between the bead 1a and the flange 1b. The joint between the shell 1 and the plate 2 is hermetically sealed by soldering, brazing or the like at 3.

As indicated above this evaporator is adapted for use in a system such as that disclosed in our pending application Serial No. 295,174. The end wall 2 of the casing is provided with liquid refrigerant inlet fittings designated in their entirety by 4 and by gaseous refrigerant and oil outlet fittings designated in their entirety by 5. Referring first to the liquid inlet fittings, the plate 2 is apertured to receive a tubular inlet valve fitting 6 which is formed with a shoulder that bears against the outer side of the plate 2 and with lugs 6a, 6a which are drilled and tapped to receive cap screws 8, 8a which serve to secure an inlet pipe fitting 8 to the valve fitting 6. The fitting 6 is hermetically sealed in the aperture of the plate 2 and a circular f'lange 6b of the part 6 fits within a corresponding groove in the part 8 and compresses a soft metal packing 9 therein,

thus forming a gas tight joint between the fittings 6 and 8. A fianged tubular part 7 is threaded into the fitting 6. A fine wire gauze strainer or filter 10 is disposed between the fittings 7 and 8 so that all liquid passing through these fittings is filtered.

A needle valve 11 is slidably mounted in the bore of the fitting 6 at the inner end thereof so that the valve engages the end of the bore of the part 7 which thus serves as a seat for the valve. The needle valve is preferably turned from triangular rod stock so that free passageway for the liquid is afforded between the body of the valve and the bore in which it is slldablykmounted. On the inner end of the fitting 6 is rigidly secured afioat bracket 12 on which the arm 13 of a, float 14 is pivotally secured by a pivot pin 15. The float arm 13 has an upward extension 13a which engages/the adjacent end of the needle valve 11 so as to move the latter toward its seat when the float 14 rises, the rising and fallin movements of the fioat being guided by its pivotal support. The bracket 13 also has a stop extension 13b which is adapted to engage the under side of the bracket 12 and limit the downward movement of the float. The fioat 14 is in the form of an open topped receptacle approximately let fitting 16 which is soldered or brazed in the plate 2 so that a hermetic seal is effected between the two parts. To the fitting 16 a pipe fitting 17 is secured by tap screws 18, 18, a gas tight joint between the two parts being effected by an interposed soft metal gasket 20. The fitting 17 is adapted to be connected to the suction pipe leading to the inlet of the compressor of the system in which the evaporator is adapted for use.4 In the bore of the inner end of the fitting 16 is secured a' tube 21 which has its inner end bent downward at right angles to the outer end so as to depend` within the cavity of the fioat 14 and have its lower open end .slightly below the top of the trough-like section 14a of the bottom of the fioat 14. 22 is a plate, preferably of sheet copper. which is secured at its upper end to the inner side of the top portion of the side wall l of the evaporator casing. This plate depends within the cavity of the fioat 14 with the lower end of the plate extending well down-into the trough section 14a of the float but with sufficient clearance between the bottom of the plate and the float to permit the relatively small necessary movement of the oat.

Assuming that the evaporator is coupled up in a system such as that described in our pending application referred to, in yother words, that the inlet fitting 8 is connected to a refrigerant condenser which in turn is connected to the discharge of a motor operated compressor and that the outlet fitting 17 1s connected to the inlet or suction opening of the said compressor, the movement -of the fioat 14 serves, by the operation of the needle valve 11, to maintain a predetermined volume of liquid refrigerant, or combined refrigerant and lubricant, in the casing of the evaporator. The evaporator is designed to operate upon the same principle as the evaporators disclosed in our said application Serial No. 295,174. That is to say, the float 14 is so designed as to size and weight that it is adapted to maintain the level of the liquid in the evaporator at such a distance below the top opening of the float that the effect of the ebullition of the li uid in the evaporator is to carry over into t ie float eX- cess or surplus lubricant as it accumulates in f the evaporator. As is explained in great detail in our application Serial No. 295,17 4 this latter action can be secured in either of several ways depending upon the depth of the liquid in the evaporator, the rate of heat transfer, the character of the refrigerant employed, etc. Assuming that a refrigerant such as sulphur dioxide and a lubricant in the form of a suitable mineral oil are employed, the oil being lighter than the refrigerant and only partially soluble therein, will float upon the refrigerant as excess oil accumulates incident to the evaporation of the liquid refrigerant. With the weight ofthe float 14 suitably proportioned to its size, the normal (quiescent) level of the liquid in the evaporator can be maintained at such a distance below the top opening of the float that the temporary increase in the volume of the liquid in the evaporator caused byl the ebullition when the compressor starts and before the gasified refrigerant has had time to escape from the upper surface of the liquid, is such that the top surface of the liquid, consisting for the most part of lubricant, will rise above the top of the float so that some of the excess lubricant can fiow into the float. The lubricant which thus enters the float finds its way into the trough 14a at the bottom theretively rapid the operation may be somewhat i the desired result.

With the float suitably desi ned as to weight and size its height above t e normal liquid level may be made such that some of the foam formed in the manner stated will fall or flow over into the float and gradually settle and consolidate in the bottom of the float until the liquid level rises therein near enough to the end of the tube 21 for the suction to draw the liquid out of the evaporator. An action such as this last referred to may occur in-the case of refrigerante such as sulphur dioxide or in the case of a refrigerant such as ethyl chloride, in which latter refrigerant the lubricating oil is completely soluble, at least within the limits of the proportions of oil and refrigerant which are suitable for use. In a word, whatever the refrigerant used, the operation is to cause excess lubricant to be delivered from the body of liquid in the evaporator into the cavity of the float so that it can be drawn by the suction of the compressor back to the latter.

As pointed out in our application Serial No. 295,17 4, above referred to, the height to which the side wall of the float should rise above the normal, quiescent level of the liquid in the evaporator in order to insure separation of the lubricant from the liquid refrigerant and discharge of the separated lubricant from the evaporator, must be determined, in the design of any specific apparatus, in relation to other factors which will vary for different designs. Such factors include particularly the relative depth of the liquid refrigerant in the evaporator and the heat load (rate of heat transfer) to be carried by the evaporator. The heat load, in turn, depends upon the size or area of the evaporator walls contacted by the liquid refrigerant, the capacity of the compressor, etc. When the heat load is to be widely variable, the maximum rate of heat transfer is, of course, to be taken into account in determining the height of the float walls, as well as the proportions of other parts of the evaporator structure. Such considerations will enable the designer to estimate roughly the height of the float Wall for any specific apparatus and if, on trial of the apparatus, such height proves too great or too small to effect the deslred separation and discharge of lubricant, it can be altered to give In such trial of a newly designed evaporator the functioning of the oil return can readily be checked by making a' short section of the evaporator discharge line of suitable glass tubing, the passage of oil or of mixed oil and liquid refrigerant being clearly visible and distinguishable through the glass wall of the tube.

In the use of evaporators of the flooded type, as heretofore constructed, in the case, for example, of domestic or household refrigerators, the upper part of the evaporator casing which is not in contact with the liquid warm air going` over from the food compartment strikes this top part ofthe evaporator first and as a result this top art of the evaporator may not frost up. ometimes,4 however, the temperature control of the systeln is set sufficiently low so that the metallic conduction of heat through the side walls of the evaporator will correct or at least partially correct this trouble. But often at the top of the operative cycle, i. e. just before-thecompressor starts, the top portion of the evaporator will become warm enough to melt olf the frozen moisture on it causlng the water to flow down until Vit strikes the colder part of the evaporator Where it again freezes. This results in a very unsightly appearance ofthe evaporator as it is not unlformly frosted over. and builds out a considerable ice for mation on its sides. i

In our improved evaporator which has been ydescribed this objectionable feature is obviated by the provision of the depending copper plate 22. The lower portion of this plate, in the operation of the evaporator, is immersed in the li quid which accumulates in the trough 14 of the float. While this liquid consists chiefly of lubricant it does contain a small amount of refrigerant dissolved therein and the relatively warm plate depending into the liquid gives up its heat to the latter with resultant evaporation of the refrigerant and cooling of the lower part of this plate 22. By reason of the high heat conductivity of the copper plate heatis thus more rapidly drawn from the top wall of the evaporator and delivered to the liquid in the evaporator. It is obvious that this action can be secured by the provision ofanysortofheatflowpathof high conductivity between the top wall of the evaporator and the liquid therein, whether the beat flow path lead to the liquid within the float or outside the float. I prefer, however, to have the plate constituting the heat flow path contact with the liquid in the float since the complete evaporation of the refrigerant Y before it leaves the evaporator is thus more perfectly assured.

It isto be observed that the casing or wall structure of the evaporator above described can be produced at low cost because of the simplicity of its construction, the wall proper obviated. The use of this type of construction is made possible by the fact that all parts of the valve mechanism, which are the only parts that are at all likely to get out ofA order, can readily be removed from the evaporator by simiply disconnecting the fitting 8 from the tting 6 by the removal of the two tap screws. This permits removal of the filter 10 and the valve seat member 7. And after the valve seat member has been removed the valve proper 11 can also readily be withdrawn for inspection and repairs or replacement if need be. The fioat part of the mechanism in the evaporator, if properly constructed inthe first instance, is not likely to get out of order since the open construction of the float makes it possible to form the body of the latter in a single piece. It is to be observed too in this connection that this type of fioat can be produced atlow cost sincethe walls of the float can be made of relatively thin sheet metal because it is never subjected to unbalanced pressures other than the relatively small pressures incident to the hydraulic head to which the float is subjected. It will be observed that the relatively small free movement of the float which is permitted by the stop 13b minimizes danger of injury tov the arts during shipment of the apparatus.

se of the copper plate 22 obviously overcomes -the above described difiicultv incident to uneven frosting and melting in a very simple and inexpensive manner.

In Figs. 4 and 5 we have illustrated a slight modification of the construction shown in Fig. 1, the modification relating to the formation of the joint between the parts 1 and 2 of the evaporator casing. In the modified construction the plate 2 at its outer periphery is rabbeted to receive a packing ring 23. of soft metal. In manufacture this soft packing ring is placed in position as .l shown in Fig. 5 before the end of the casing section 1 is flanged inward. When this latter Hanging operation is performed the wall of the casing section 1 is forced inward around the soft packing ring so as to subject the latter to heavy pressure and effect a tight seal between the casing sections 1 and 2. j

Referring now to the form of construction illustrated in Figs. 6 and 7, the evaporator casing in this construction comprises a drawn or pressed metal casing section 31 which forms the cylindrical side walls and one end wall of the casing and a second section 32 .which constitutes the other end wall of the casing. The side Wall of the section 31 at its open end is formed with a bead 31 which serves as an abutment for the flanged periphery of the part 32 and the edge of the side wall of the section 31 is folded over the flange of the part 32 and a. gas tight joint formed by soldering or brazing at 33.- The opposite end wall 31b is provided with liquid refrigerant inlet fittings designated in their entirety by 34 and by gaseous refrigerant and oil outlet fittings designated in their entirety by 35. In the case of the inlet fittings, the wall 31b is apertured to receive an apertured member 36 which has a flange that bears against the inner side of the end wall 31 and is secured to the latter by soldering or brazing in the well known manner. To this member 36an inlet pipe fitting 37 is secured by means of tap screws 38, soft metal packing 39 being interposed between the two parts to effect a gas tight joint. In the nipple like extension 37a of the fitting 37 is secured a tubular member 40 which carries the inlet valve of the evaporator. The valve mechanism comprises a tubular valve seat member 41 having a. seat at 41 for the needle valve 42, the latter being formed from triangular rod stock. The member 41 carries a tubular wire gauze strainer or filter 41h. The member 41 is held in position in the end of the tube 40 by means of a cap 43 which is threaded on the end of the said tube. The valve 42 has a rod like extension 42n which extends through an aperture of larger diameter than said extension in the end of the cap 4 3. A. bell crank 44 is pivotally mounted on a pin 45 carried by supporting lugs 43a on the cap 43. The upper arm of the bell crank engages the extension 42a of the needle valve while the horizontally extending arm of the bell crank is engaged by a depending loop o-r bale 46 of the open topped, cup-shaped float 46 which serves in this manner to actuate the valve and maintain a predetermined amount of liquid in the evaporator. The float 46 is guided in its movement in part by an upstanding plate 47 which is secured to the bottom part of the side wall of the casing and in part 'by a tube' 48 which is secured to the bottom of the fioat on the inside thereof and loosely fits the depending portion of a discharge tube 49 which is rigidly secured to the end wall of the casing as will presently be explained. The float is guided for vertical movement by the tube 49, the latter thus performing a double4 function. Also it is held against unlimited rotational movement by the plate 47 so that the bale 46 is kept in operative engagement with the bell crank 44. In addition, the tube 40 and plate 47 below the float and the horizontal section of the tube 49 above the float limit its axial movement so that it is not subject to danger from free movement when the apparatus is handled in shipment.

The outlet tube 49 is secured in a member 50 which constitutes a part of the discharge fittings 35, the part or member 50 being secured in an aperture formed in the end wall 31b of the casing above the inlet fittings 34. A pipe fitting 51 is secured to the part 50 by tap screws 52, a gas tight joint being insured by the use of a soft metal packing 53.

The last described evaporator operates upon the same principle as the one first described and a brief reference to the mechanical features of the operation will therefore sufiice. Liquid refrigerant or combined refrigerant and lubricant entering` through the inlet fitting 37 is permitted to pass the needle valve 42 into the evaporator when the level of liquid in the evaporator falls and permits the float to correspondingly lower its position and in this manner the float maintains a predetermined mass of liquid in the evaporator. Lubricant separated'from the main mass of the liquid in the evaporator in 'either of the ways explained in connection with the first form of evaporator, on iiowing into the cavity of the float 46 is drawn out through the tube 49 by the suction of the compressor, the liquid lubricant having free access to the lower end of the tube 49 through notches formed in the guide tube 48.

In case inspection, repairs or renewal of any of the inlet valve parts becomes neces- Y sary the entire valve assembly can readily y be removed by simply removing the tap screws 38. In this connection it will be observed that the bale 46a of -the float is formed with a sloping lip 469 to facilitate reengagement of the valve operating bell crank 44' with the bale when the valve assembly is restored to its operative position. As in the first form of construction the fact that the .valve mechanism can thus readily be removed from the evaporator casing and the further fact that the float mechanism is such as not to get out of order, make it feasible to use the permanently closed form of casing construction Which can be produced-at relatively low cost. The float in the second form of construction, as in the first form of construction, can be made at lowv cost as the wall proper of the float can be formed from a single piece of light sheet metal. Again, in both forms'of construction the upright end Wall of the evaporator carries all parts of the evaporator controlling the admission and discharge of refrigerant and oil and this assembly of the parts upon the one end wall structure facilitates .manufacture and provides a self-contained unit applicable to various forms of evaporators.

It will readily be appreciated that the use of a simple cup-shapefloat, that can be formed from relatively thin sheet metal, to control the inlet of liquid refrigerant to the evaporator provides a' construction that can be produced at -very low cost. This is rendered feasible by the arrangement of the gaseous refrigerant discharge tube in such a way that the suction of the compressor Will remove any liquid that finds its way into the ioat and thus maintain the necessary buoyancy of the float. While, in the normal operation of the preferred form of the invention the liquid thus removed from the float is lubricant, it is to be observed that under some conditions the liquid to be removed from the float may be refrigerant alone. For example, in the shipment of apparatus of this character charged with refrigerant, the liquid refrigerant in the evaporator is practically certain during shipment, and before any lubricant may have entered the evaporator, to be splashed into. the cavity of the float and when the apparatus is first placed in operation the suction of the compressor serves to quickly remove this liquid refrigerant and permit the float to operate in its normal manner. Accordingly the advantage of the construction is not limited to the removal of lubricant from the evaporator.

It should be understood that the invention is not limited to the specific forms of construction which have been illustrated for purposes of explanation but that it can be embodied in a great variety of forms of construction vwithin the scope of the appended claims.

What we claim is:

1. In an evaporator for refrigerating apparatus, the combination of a casing structure having an upright wall with an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant and oil; a valve for controlling the said inlet passage; an open topped, cup-shaped float in the casing for actuating said Valve; and a discharge conduit for gas and oil connected to the aforesaid outlet passage and having its inlet within the cavity of the float.

2. .In an evaporator for refrigerating apparatus, the combination of a casing structure having an upright Wall with an inlet passage for liquid refri erant and an outlet passage for gaseous re rigerant and oil; a valve for controlling the said inlet passage; an open topped, cup-shaped float in the casing for actuating said valve; means, comprising a part supported by said upright wall,

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for guiding the movement of the float to float in the casing for` actuating said valve;

means, comprising a part supported by said upright wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas and oil connected to the aforesaid outlet passage and having i-ts inlet within the cavity of the float. n

4. In an evaporator for refrigeratmg apparatus,- the combination of a casing structure having an upright wall with an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant and o1l; a valve for controlling the said inlet passage, said valve and its seat being removable from the evaporator Without` removal of any of the wall sections thereof; an open topped, cupshaped lioat in the casing for actuating said valve; means, comprising a part supported by said upright Wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas and oil connected to the aforesaid outlet passage and having its inlet Within the cavity of the float.

5. In an evaporator'for refrigerating apparatus, the combination of a casing having an upright wall section permanently secured to the remaining vvall structure and having an inlet passage for liquid refrigerant and an outlet assage for gaseous refrigerant and oil; a va ve for controlling the said inlet passage; an open topped, cup-shaped float in the casing for actuating said valve; means, comprising a part supported by said upright Wall, for guiding the movement of the ioat to actuate said valve; and a discharge conduit for gas and oil connected to the aforesaid outlet passage and having its inlet within the cavity of the float.

6. In an evaporator for refrigerating apparatus, the combination of a casing having an upright Wall section permanently secured to the remaining Wall structure and having an inlet passage for liquid refri erant and an outlet passage for gaseous re rigerant and oil; a valve for controlling the said inlet passage, `said valve being removable from the evaporator without removal of any of the wall sections thereof; an open topped, cupshaped Boat in the casing for actuating said valve; means, comprising a part supported by said upright wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas and oil connected to the aforesaid outlet passage and having its inlet Within the cavity of the float.

7. In an evaporator for referigerating apparatus, the combination of a casing having an inlet passage for liquid refrigerant and an outlet passage'for gaseous refrigerant and oil; mean for maintaining a body of liquid refrigerant at a predetermined normal level in the casing; an open topped receptacle in the casing adapted to receive lubricant separated from the body of liquid in the casing by ebullition; a discharge conduit for gaseous refrigerant and oil connected to the said outlet passage and having its inlet within the said receptacle; and a metal plate of high heat conductivity arranged in the casing with its upper edge in contact with the inner Wall of the casing above the liquid level therein and its lower part depending into the said receptacle and adapted to Contact with -liquid therein. u

8. In an evaporator for refrlgeratmg apparatus, the combination of a casing havlng an inlet passage for liquid refrlgerant and lan outlet passage for gaseous refrigerant and oil; a valve for controlling the inlet passage; an open topped, cup-shaped float in the evaporator for actuating said valve and malntaining a body of liquid refrigerant therein at a predetermined normal level, said float being adapted to receive lubricant separated from the liquid refrigerant by ebullition; a discharge conduit for gaseous refrigerant and oil connected to the said outlet passage and having its inlet Within the cavity of the float; and a metal plate of high heat conductivity disposed in the casing with its upper edge in contact with the inner Wall of the casing above the liquid level therein and its lower part depending Within the cavity of the float and adapted to contact with liquid therein.

9. In an evaporator for refrigerating apparatus, the combination of a casing structure having an upright wall with an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant; a valve for controlling the refrigerant inlet passage; an open-topped, cup-shape float in the casing for actuating said valve; and a discharge conduit connectedto the refrigerant outlet passage and having its inlet within the cavity of the float.

10. In an evaporator for refrigerating apparatus, the combination of a casing struc- -ture having an upright wall with an inlet passage for liquid refrigerant and an outlet passage forgaseous refrigerant; a valve for controlling the said inlet passage; an opentopped, cup-shape float in the casing for actuating said valve; means, comprising a part supported by the said upright Wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas connected to the aforesaid outlet passage and aving its inlet within the cavity of the oat.

11. In an evaporator for refrigerating apparatus, the combination of a casing structure having an upright wall with an inlet passage for liquid refrigerant and an outlet passage for aseous refrigerant; a valve for controlling t e said inlet passage, said valve being removable from the evaporator Without removal of any of the wall sections thereof; an open-topped, cup-shape float in the casing for actuating said valve; means, comprising a part supported by said upright wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas connected to the aforesaid outlet passage and having its inlet Within the cavity of the float.

12. In an evaporator for refrigerating apparatus, the combination of a casing structure having an upright wall with an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant; a valve for controlling the said inlet passage, said valve and its seat being removable from the evaporator Without removal 0f any of the wall sections thereof; an open-topped, cup-shape ioat in the casing for actuating said valve; means, comprising a part supported by said upright wall, for guiding the movement of the iioat to actuate said valve; and a discharge conduit for gas connected to the aforesaid outlet passage and having its inlet within the cavity of the float.

13. In an evaporator for refrigerating apparatus, the combination of a casing having an upright Wall section permanently secured to the remaining wall structure and having an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant; a valve for controlling the'said inlet passage,

said valve being removable from the evaporator Without removal of any of the Wall sections thereof; an open-topped, cup-shape iioat in the casing for actuating said valve; means, comprising a part supported by said upright Wall, for guiding the movement of the float to actuate said valve; and a discharge conduit for gas connected to the aforesaid outlet passage and having its inlet within the cavit 02E the float.

14. In re iger-ating apparatus, the combination of a wall structure adapted t0 form part of the waH of an evaporator casing, said Wall structure having an inlet passage for liquid refrigerant and an outlet passage for gaseous refrigerant; a valve for controlling the refrigerant inlet passage; an open topped, cup-shape ioat operatively connected to said wall structure for actuating said valve; and a discharge conduit connected to 'the said refrigerantoutlet passage andy having its inlet within the cavity of the float.

In testimony whereof, we hereunto aix our signatures.

HERBERT C.. KELLOGG. EDWARD M. MAY. 

